Microservice Solution: Logging

You must have an VCP Business or a higher license to be able to create a microservice solution.

The VCP Studio microservice solution template is fully configured for logging. All the services, applications and gateways are configured to use the Serilog library for structured logging. They are configured in a common way for logging. This document explains that common logging structure.

The Serilog Sinks

The Serilog library is configured so it writes the logs to the following targets (a.k.a. sinks) in parallel:

• Console: Logs are written to the standard output of the executing application. Logging to console is useful when you want to see logs easily while it is running in a container.
• File: Logs are written to a file named logs.txt located under the Logs folder of the executing application. File logging is useful when you run the application on your local computer. You can check logs easily when you have a trouble. This sinks is only configured for DEBUG mode. It won't be available in your production environment (you can change the behavior in your Program.cs file).
• ElasticSearch: Logs are sent to an Elasticsearch server. Elasticsearch is especially useful when you want to search and trace the logs. This microservice solution is also includes a Kibana container configuration, so you can visualize and search your logs easily. See your appsettings.json file for the Elasticsearch configuration.
• VCP Studio: This is a Sink provided by VCP Studio. It sends all logs to VCP Studio, so you can easily monitor your logs in real-time on your VCP Studio Application Monitoring panel.

The solution can work with any sink supported by Serilog. You can add more sinks, remove pre-installed sinks or fine tune their configuration for your solution.

Program.cs

The Program.cs file is the main point that configures the logging system. It is done here, because we want to initialize and start the logging in the very beginning of the application.

Additional Information

You can easily understand the Serilog configuration when you check your Program.cs. However, there are a few things worth mentioning here:

• We are adding an Application property to every log record, so you can filter logs by the application name. It is done in the Program.cs file with the .Enrich.WithProperty("Application", applicationName) line. The applicationName value is taken from the IApplicationInfoAccessor service of VCP. By default, it is the name of the entrance assembly (that contains the Program.cs file) of the application.
• We are using VCP Serilog Enrichers in the module class of the application. It is done by the app.UseVcpSerilogEnrichers(); line in the OnApplicationInitialization method of your module class. That ASP.NET Core middleware adds current tenant, user, client and correlation id information to the log records.